The Bartlett Development Planning Unit


Tsunami risk for the Western Indian Ocean

Steps toward the integration of science into policy and practice

16 July 2017

The project investigates tsunami risk to coastal India in order to improve the scientific basis for planning aimed at preventing severe losses (in both lives and livelihoods) and increasing community resilience to catastrophic natural events.

The three central aims are:

1. To analyse the tsunami risk arising from earthquakes and quantify the uncertainties regarding eventual coastal inundations that it causes.
2. To understand how urbanisation processes, and in particular land use and planning decisions, contribute to the
impact of coastal inundation on communities
3. To assess the uncertainties regarding these impacts, the value put at risk by them and the information required by stakeholders to develop mitigation and response strategies that reflect these considerations.

Project Outline

The project takes an interdisciplinary approach that brings together natural scientific (geology-statistics) modelling of hazards, social-scientific understanding of underlying risk factors and risk communication, and decision-theoretic (including ethical) evaluation of mitigation policies. In the first short-term study, the focus is on two or three particular coastal towns in India, with the aim of laying down the foundations for a more ambitious future study. By doing an initial study of this kind the project can assess the feasibility of in depth mitigation planning that is sensitive to scientific uncertainty and to community values, and trial a multidisciplinary approach to managing natural hazards.

The project first investigates tsunami risk arising from giant earthquakes on the Makran Subduction Zone (MSZ). Tsunamis from this source threaten the West coast of India including major cities such as Mumbai. The best documented historic tsunami from the MSZ occurred on the 28th November, 1945 when around 300-4000 people were killed in several countries with Arabian Sea coastlines, including India, at a time when these coasts were much less populated than today. However, large uncertainties in the possible sources of tsunamis around India are key issues for tsunami risk assessment for the coast of India.

In 2004, the lack of awareness and preparedness to a possible tsunami arising from the Sumatra-Andaman (S-A) fault unfortunately contributed to the death of around 15,000 people on the Eastern coast of India, with a catastrophic economic impact on poor and fragile local communities. The prospect of similar losses for a future event on the Western coast compels scientists, specialists of humanities, and social scientists experts in planning for natural hazards, to jointly investigate the risk as proposed here.

In order of priority, the project's first objective is to improve the scientific understanding that underpins prevention strategies such as hazard mapping for urban planning. Its second objective is to explore the processes that will enable the incorporation of scientific assessments into policies and practice, in order to ethically and efficiently protect vulnerable and poor communities from future tsunamis. Its third objective is to identify the hurdles that would hamper the integration of science, policies and practice, and propose specific strategies towards pragmatic decision-making under severe uncertainties.


UCL Statistical Science (lead), Indian Institute of Science, LSE